Imaging System Hardware
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the filter wheel. Different manufacturers have different conventions, so if
you obtain a filter from a third-party, consult with the manufacturer’s
documentation in order to determine the correct orientation. Once you
determine the orientation of the filter, carefully drop it into position; a small
hex key or similar object can be used to gently maneuver the filter into the
seated position—do not touch the optical surface as this will irreparably
damage the filter, but it is safe to touch the black mounting ring. Next,
secure the filter in place with the threaded metallic ring using the filter ring
tool. It is advisable to record the filter information and position number on
a piece of paper. Install additional filters if desired, and replace filter wheel
cassette back into the scanner. The access panel must be securely closed
before scanning can be resumed. To uninstall a filter, perform this
procedure in reverse order.
The filter information is stored in the PC board of the scanner (not the
computer). After each filter installation or change is made, turn on the
scanner and open the
Filter Tool
program, located in the Axon Laboratory /
GenePix Pro 5 folder of the start menu. Activate the filter position by
pressing on the check box, and enter a description that will help you
identify the filter. There are two fields available for each position in which
you can enter filter information. We recommend that you use the filter
supplier’s designation as the “Official name” and an easily recognizable
description for “Alternative name” such as the dye name (
e.g.,
FITC, Texas
Red.)
Photo-Detection
The GenePix scanner uses a high-sensitivity, low-noise photo-multiplier
tube (PMT) to detect the emitted fluorescent light. Loosely defined, PMTs
are optical components that convert incident photons into electrons via the
photoelectric effect. When an incident photon impinges on the active
surface of the PMT (the photocathode), an electron is generated. This
electron flows through a series of electron multipliers (dynodes) to the
Chapter 4
